Interpretive Summary: High nutrient levels in surface runoff from intensive animal production areas often promote excessive algae growth in streams and lakes, and lead to serious water-quality problems. Expansion of confined swine production in some regions of the United States has raised concerns that swine manure applications may threaten water quality in those areas. For example, increasing swine production in the Buffalo National River watershed is believed to be partly responsible for declining water quality in that scenic national park. Swine manure is usually surface applied to pastures and hay fields, but better management of manure applications may be required to adequately protect water quality. Therefore, research is needed to help identify the best sites and methods for manure applications. This research found that concentrations and mass losses of water-soluble nutrients in storm runoff from pasture increased significantly following swine manure applications, and doubled when manure application doubled. Infiltration rate (the rate at which rain soaks into a soil) ranged from 0.3 to 2.4 inches per hour. Soils that had a high infiltration rate produced less storm runoff (as expected), but also had lower concentrations of the soluble nutrients in storm runoff. Concentrations of nitrate and ammonia at the 16-inch depth in the soil did not increase following swine manure applications. Nutrient loss in runoff from manure applications can be a serious threat to water quality, but information from this research can help agricultural producers make better manure management decisions to protect water quality while maintaining high levels of production.